This is way, way old school, but it’s still my favorite moment from a game.
In high school we used to play a game at school called “Bedlam”. It was a text game for the TRaSh-80, in which the object was to escape from a mental hospital. You controlled your character by typing in commands like “Get green key” or “Look west.” We’d all been playing it off and on for years and no-one had even come close to solving the darn thing.
Then one day, when I was fooling around after Olympics of the Mind practice, I started ordering the other residents of the hospital around. “X-Ray look west” I typed at one stage. “X-Ray says he sees a secret door!” quoth the computer. I immediately locked X-Ray in the room, then went around collecting all the other residents and brought them one by one into the room. I then asked each of them in turn to open the secret door. The last one left was “Napoleon.” “Napoleon grabs the door with both hands and busts it open. The door leads to the outside…you’re free!”
After two years, the game had been won! I started racing around the room like a chicken with its head cut off. Nothing could ever beat that in a game, ever.